Materials are known in the prior art for use as insoles in shoes, boots and apparel for absorbing perspiration and body fluids and for overcoming odors generated by such perspiration and body fluids as is shown in U.S. Pat. NoS. 5,392,533; 5,197,208; 4,864,740 and 4,517,308.
The present invention provides an improved material and method for making such material particularly adaptable for use in shoes, body pads and apparel but not limited thereto which in one preferred embodiment has a cover layer and a hydrophilic foam layer bonded thereto to facilitate absorbing, adsorbing, transferring, gelling or storing and dissipating body fluids generated by the body or body functions and other moisture. In particular, the hydrophilic foam layer is formed from a polymerized combination of an aqueous mixture, including one or more sorbents and possibly additives, with a predetermined quantity of hydrophilic urethane prepolymer, thereby enhancing the ability of the hydrophilic foam layer to draw body fluids or other moisture off and through the cover layer and absorb, adsorb, gel or store and dissipate such body fluids and moisture.
Another aspect of the present invention is to provide an improved material and method for making such material for the same objects and purposes above described in which a third or bottom layer is bonded to the side of the foam layer remote from the cover layer, such third layer being in the form of a non-woven fiber or a felted non-woven fiber material to provide stiffness or thermoformability to the composite material.
It has been found that a composite material having a foam layer formed from predetermined ratios of (1) an aqueous mixture of one or more sorbents and a thermoformable acrylic latex emulsion and (2) a hydrophilic urethane prepolymer enhances the ability of the composite material to be thermoformed into shaped components and thus maximizes the use of the composite material for products utilized in the commercial marketplace, such as insoles for footwear, incontinent pads and devices, nursing pads, protective clothing and the like type apparel and devices. The thermoformability of the composite may be further enhanced by bonding a third layer of a thermoformable non-woven fiber or a felted non-woven fiber material to the surface of the foam layer opposite the surface to which the cover layer is bonded.
The composite material so formed achieves advantageous results; for example, as an insole, it increases comfort for the user's foot:
(a) by removing perspiration generated by the foot in the shoe; PA1 (b) by leaving the upper surface of the insole dry to the touch; and PA1 (c) by creating relatively cooler surface temperatures due to the removal of the moisture from the upper surface of the insole. PA1 a. metering and mixing an aqueous mixture, including a sorbent, surfactant and adequate water, with a predetermined ratio of hydrophilic urethane prepolymer to provide a polymerizing mixture for forming the foam layer of the composite material, PA1 b. depositing the polymerizing mixture on releasable bottom paper disposed on a moveable carrier and covering the upper surface of the polymerizing mixture with releasable top paper as the polymerizing mixture is moved with the carrier, PA1 c. advancing the polymerizing mixture in the top and bottom release paper by moving the carrier and sizing the foam layer being formed to the desired thickness until it is tack free, PA1 d. sequentially removing the top and bottom releasable paper and simultaneously drying the sized and formed foam layer to remove residual moisture, PA1 e. applying a cover layer of random oriented hydrophobic fibers to the formed and dried foam layer, and PA1 f. connecting the foam layer and cover layer and removing the formed composite material from the carrier. PA1 e(1). adding non-woven fiber web or a felted non-woven fiber material selected for its stiffness or thermoformability as a bottom layer to the side of the foam layer remote from the cover layer, PA1 e(2). connecting the cover layer, foam layer and non-woven fiber web or felted non-woven fiber web material, PA1 e(3). thermoforming the cover layer, foam layer and non-woven fiber web layer to form the composite material, and PA1 e(4). die cutting the composite material to provide sized and shaped articles.